Earlier quoted context omitted.
I don't remember where I was five years ago and what Facebook was saying, but if you look at this graph http://en.wikipedia.org/wiki/File:Facebook_popularity.PNG at 2007, and remember what Facebook is (since day 1), it's pretty easy to see Facebook making the argument that it will be used by pretty much everyone, everywhere. It's pretty obvious that pinterest has no such claim. That is one such basis. Other such base…
You're being pedantic about the 5 year thing, if anything Pinterest's current growth outpaces that of Facebook. At 2 years old they're sitting at somewhere around 30M users, even Facebook didn't grow that quickly (per your own graph). In addition, Pinterest sits much closer to transactions than Facebook does. Facebook currently makes around $5/user/year, just given Pinterest's proximity to the transaction its relativ…
For one thing, Facebook was .edu limited for its first two years, so its growth was constrained. Rather than that, look at Facebook's growth from 2007-2009.